In the manufacture of thermoplastic containers by the shuttle blow molding process, the threaded or otherwise configured closure receiving neck portion of the container, which is commonly referred to as the "finish" of the container, is formed by a neck mold that is positioned against an outermost end surface of a body mold cavity in which the body portion of the container is blown from a previously extruded form or parison of the container. The blowing of the container is done by air or another gas that is introduced into the parison within the mold cavity by a blow pin that extends through the neck mold into the parison within the body mold. The blow pin reciprocates with respect to the neck mold and body mold, and an anvil of a hard material is positioned within an open-ended cavity on the outermost surface of the neck mold to prevent impact damage to the neck mold as the blow pin reciprocates with respect to the neck mold.
In the manufacture of thermoplastic containers by the extrusion blow molding process, heretofore it has been very difficult to produce a container with an internal control diameter at or near the top of its finish, the "C" dimension in industry nomenclature, than the minimum internal diameter at or near the bottom of the finish, the "I" diameter in industry nomenclature. However, for proper dispensing of the packaged product, when the packaged product is a liquid, it is often important that the size of the opening at the "C" dimension be substantially smaller than the "I" dimension. Heretofore, this has usually been accomplished by inserting a separate annular fitment in the outlet of the container finish. This added element, and the assembly step involved in its insertion in a container, however, add to the expense involved in the manufacture of restricted outlet liquid containers by the extrusion blow molding process.
Another problem encountered in the manufacture of thermoplastic containers by the extrusion blow molding process, according to prior art techniques, relates to dimensional variations in the rims of such containers resulting from the time required to properly cool the portion of the container to be removed from the rim, often called a "moil," at the conclusion of the blow molding process.
Another problem encountered in the manufacture of thermoplastic containers by the extrusion blow molding process, according to prior art techniques, relates to the removal of the moils from the containers at the conclusion of the molding process, especially containers produced with a restricted outlet. Heretofore, stripper plates, which are conventionally used to remove moils from other types of extrusion blow molded containers, were not effective in removing moils from restricted outlet containers of such type, and such moils often disengaged from the containers in an uncontrolled manner upon impact of the containers with a removal conveyor.